1. Field of the Invention
The invention relates to a connector for a flat multilayer element that comprises a first rigid glazing pane provided with one or more electrical functional elements and a second rigid glazing pane joined flat to that side of the first rigid glazing pane that is provided with the functional elements, this second pane having at least one cutout for making an electrical connection to the functional elements.
The invention also relates to a flat element equipped with such a connector.
2. Description of Background Art
It is generally known that systems based on thin electrically conducting layers may be use as resistance heating elements by applying an electrical voltage. There are many applications of this technique both in the automobile sector and in the building sector.
In general, these multilayer systems deposited on flat substrates, for example window glazing, comprise at least one metal layer, for example made of silver, and (for transparent multilayer systems) dielectric layers on both sides of the silver layer and, optionally, also blocking layers made of various materials, and among these also covering layers for increasing the mechanical strength capability of the multilayer structure. In many cases, the infrared radiation reflection properties of multilayer systems are also used as thermal insulation.
To establish a uniform current density in these multilayer systems used as heating layers is usually a problem. It is necessary above all to prevent areas being locally overheated by high current densities, called hot spots. To achieve this, and in many applications, the heating layer is provided with plane electrodes in the form of a ribbon. They consist, for example, of thin metal ribbons deposited or attractively colored and electrically conducting, which are printed and optionally baked, and they allow the current to be introduced and removed over as wide a base as possible. However, in most cases, these connections do not meet optical/esthetic requirements and must consequently be masked. Since in many applications, for example for vehicle windows, they are mostly located along the edge of the substrate, they can be produced with little workmanship.
It is also known, in such heating layers, how to vary the flow and distribution of the current by means of fine lines that divide the heating layer into individual current paths or sections electrically connected in parallel to one another, and the ohmic resistances of which are if possible all the same.
German patent application 10208552.8 discloses a plate element provided with an electrically conductive coating (“heating layer”) that is suitable for being connected directly to the voltages of the usual mains in the domestic field. It is essentially formed from a multilayer composite structure that comprises a first rigid pane, with the heating layer deposited on it and an adhesive layer, and a second rigid pane. In the electrical connection region of the heating layer, the second rigid plane is provided with a bore. In this bore, two regions of different polarity of the heating layer are located in close proximity. Provided in each of these regions is an electrode applied to the heating layer, to which electrode a current lead is joined by soft solder. The current flow between the two connection terminals belonging to the same heating layer is guided, as already mentioned, by dividing up the heating layer by means of fine lines.
DE-U1-20 107 908 discloses a connector in which a glazing unit coated so as to be electrically conducting is provided with retaining elements that are in the form of clamping fittings serving at the same time as supports for electrical contacts. Resilient tabs incorporated into the clamping fittings are applied so as to be electrically conducting on the coating of the glazing unit and pressed against the latter.
In another context, DE-A1-19 958 879 discloses an insulating glazing unit provided with a composite glass pane, the adherent layer of which includes functional elements (solar cells). These electrical connection conductors are each passed through a cutout made in one of the panes of the composite and in the opposite rigid pane of the insulating glass, that region of this penetration into the intermediate space of the insulating glass between these panes being surrounded by a spacer of annular shape. The conductors may also be passed through a hollow pin of a point support that is used for fastening the insulating glazing unit to a subjacent structure.
In the field of fittings and fastenings for composite glazing units, DE-A1-3 908 983, DE C2-4 325 024 and DE-U1-8 701 693 teach the technique consisting in providing, in the rigid pane, cutouts into which the fastening elements may be inserted and fastened. These fastening elements may have projections in the form of a radial flange which extend into the adhesive layer of the composite and which, when the assembly is completed, engage via the rear in the glazing unit. Their cutouts may optionally have an undercut. In the latter case, undercut-engaging pegs are also described for composite glass fastenings (DE-A1-3 811 249). The surface of the other side of these composite glazing units each time remains entirely intact. The last mentioned sources do not concern electrical connectors.